PROVISION FOR UPKEEP
ture F is also of cast iron and has a bearing all around on the base, while the central stud C is used as a locator for the work at its upper end, and holds the revolving portion down firmly by means of the nut and collar at H. The fitting at this point is such that the fixture may be revolved readily and yet is not free enough so that there is any lost motion. A liner bushing of hardened steel is ground to a nice fit on the central stud at E
Machinery
Fig. 3. Indexing Fixture used for Milling Teeth in Clutch Gear
and will wear almost indefinitely, while an indexing ring L is forced on the revolving portion F of the fixture, and doweled in its correct position by the pin V and held in place by the four screws R. The work is held down firmly on the revolving portion by means of the three clamps /, these being slotted at K to facilitate rapid removal.
A steel index bolt M of rectangular section is carefully fitted to the slot in the body of the fixture, and beveled at its inner
20 J